1. Field of the Invention
The present invention broadly relates to a pipe union assembly. More specifically, the present invention provides for a thermocouple well assembly having a thermocouple and a sealing coupling, and a method for hydroprocessing a hydrocarbon feed stream in a hydroconversion reaction zone that communicates with a thermowell member of a thermocouple well assembly. In the event that the thermowell member begins to leak hydrocarbon gas(es) and/or hydrocarbon(s) from the hydroconversion reaction zone, the present invention provides an apparatus and method that eliminates the leak(s) without having to shut down the flow of the hydrocarbon feed stream through the hydroconversion reaction zone.
2. Description of the Prior Art
Conventional practice in hydroprocessing hydrocarbon feed streams through hydroconversion reaction zones includes making temperature measurements to preclude thermal overloads. Temperature measurements in a hydroconversion reaction zone contained within a hydroconversion reactor are taken with thermocouples which are inserted in thermowells that penetrate a cylindrical wall of the hydroconversion reactor and thermally communicate with the hydroconversion reaction zone.
Thermowells are typically manufactured of relatively thin metallic material(s). Corrosion on the thin material(s) of the thermowells can cause leakage of the thermowells, which necessitates a premature shutdown of the hydroconversion reactor, as no means is presently available for temporarily stopping a leak from a leaking thermowell without having to totally shutdown the hydroconversion reactor. Since an unanticipated shutdown of a hydroconversion reactor zone is costly and time-consuming, it is desirable to continue operation of the hydroconversion reactor until the leaking thermowell can be repaired/replaced during a regularly scheduled shutdown. Some of the problems of avoiding unanticipated shutdowns associated with thermocouple/thermowell problems have been addressed in the prior art.
A patentability search was conducted and the following patents were found: U.S. Pat. No. 5,302,113 to Eichelberger et al; U.S. Pat. No. 4,510,343 to Sivyer; U.S. Pat. No. 4,137,768 to Tushie et al; U.S. Pat. No. 4,064,756 to MacLean et al; U.S. Pat. No. 4,334,334 to Wendell; U.S. Pat. No. 4,332,272 to Wendell; U.S. Pat. No. 4,331,170 to Wendell; Canadian Patent No. 1303094 to Chapman et al; Canadian Patent No. 1,045,963 to Krywitsky; and Canadian Patent Application No. 2,063,164 to Krywitsky.
U.S. Pat. No. 5,302,113 to Eichelberger et al. discloses a method for installing thermocouple on flare burner tip pilot assemblies from grade without discontinuing the operation of the flare.
U.S. Pat. No. 4,510,343 to Sivyer discloses a thermowell apparatus housing a removable thermocouple for sensing temperatures in a petrochemical furnace which includes a housing externally welded to a pipe or fitting and adapted to enclose a removable tip member of high alloy material and the removable thermocouple.
U.S. Pat. No. 4,137,768 to Tushie et al. teaches an adjustable depth tubular sheath thermowell assembly having a thermowell and a thermocouple and which permits changing the depth of extension of the well from its mounting into the environment to be sensed by utilizing compression fittings on the thermowell. The adjustable depth tubular sheath thermowell assembly to Tushie et al. also permits the replacement of the thermocouple.
U.S. Pat. No. 4,064,756 to MacLean et al. teaches a temperature sensitive instrument assembly (e.g., a combination thermowell/thermocouple) for being removably mounted in a flowline, vessel, or the like, and which includes a flange plate through which a hollow mounting tube is secured for supporting a temperature sensing element. The hollow mounting tube is provided with an opening or aperture for indirect impingement of the fluid flow through the vessel on the temperature sensing element. The fluid flow is diverted by a shield which is formed of or secured to the hollow mounting tube.
U.S. Pat. Nos. 4,334,334, 4,332,272, and 4,331,170, all to Wendell disclose a thermowell which is installed in a pipe or similar member without taking the member out of service by first welding an adapter to the surface of the member at the point where the thermowell is to be installed. Subsequently, a gate valve and a hot capping machine having a drill is connected to the adapter. A hole is drilled with the drill in the member through the open gate valve, and the drill is then withdrawn. The valve gate is closed and the withdrawn drill in the hot capping machine is replaced with the thermowell by opening the gate valve and subsequently installing the thermowell through the open gate valve.
Canadian Patent No. 1,303,094 to Chapman et al. teaches an improved pipe union comprising at least one hollow fitting member attachable to a pipe, or the like, and a sealing member also attachable to a pipe, or the like. The fitting member has a tapered ridge perimetrically formed around the end of the fitting member, which extends axially therefrom, and the sealing member has at least one perimetric tapered channel which complements the tapered ridge of the fitting member. The tapered ridge of the fitting member couples the perimetric tapered channel of the sealing member to form a fluid tight seal. In one embodiment, an external sleeve is employed to maintain the contact between the fitting member and the sealing member. The sleeve is coupled to the fitting member and the sealing member with set screws, threads, or the like.
Canadian Patent No. 1,045,963 to Krywitsky and Canadian Patent Application No. 2,063,164 by Krywitsky disclose a fastener for coupling at least two members. The fastener is generally cylindrical and has a generally C-shaped cross section and at least one barb member for engaging a surface of a member to be coupled. The fastener is generally employed in conjunction with a set screw, bolt head, or nut, or the like to serve as a counter-tamper measure. A set screw, bolt, nut, or the like is employed in the usual fashion with the fastener engaged to the set screw, bolt, nut, or the like and the member to which the screw, bolt, nut, or the like is engaged to prevent removal of the screw, bolt, nut, or the like. For example, in one embodiment the C-shaped fastener would be secured to a top face of a set screw and have at least one barb extending beyond the outer circumference of the set screw at an angle which allows rotation in a direction associated with tightening the set screw but which opposes rotation in a direction associated with loosening.
A review of the prior art reveals that the problem presented by a thermowell that begins to leak during operation of a hydroconversion reactor, and the problem of necessitating shutdown of the hydroconversion reactor to stop the leak of a leaking thermowell has yet to be addressed. Therefore, what is needed and what has been invented is effective apparatuses to prevent and/or suspend the leakage of a leaking thermowell during continual operation of a hydroconversion reactor without having to shutdown the hydroconversion reactor, and methods which facilitate rapid response to leakage of a leaking thermowell which commenced leaking during operation of a hydroconversion reactor.